/**
 * @returns {String} - 随机生成RGBA颜色
 */
export default () => {
  var r = Math.floor(Math.random() * 256)
  var g = Math.floor(Math.random() * 256)
  var b = Math.floor(Math.random() * 256)
  var alpha = Math.random() //随机生成1以内a值
  alpha = alpha.toFixed(2)
  return `rgba(${r},${g},${b},${alpha})`
}
